Field of the Invention
The invention relates to a binocular and the prism module thereof, and more particularly to a binocular capable of measuring distance and the prism module thereof.
Description of the Related Art
FIG. 1 depicts a prior binocular capable of measuring distance, with light paths shown. The prior binocular includes a left optical system 10 and a right optical system 20. The right optical system 20 includes a laser diode 52 and an organic light-emitting diode (OLED) 63 configured to produce light containing an image and a reticle message. In operation, the light containing the image and reticle message is reflected by a reflecting mirror 58, enters a prism module 22, is reflected by the prism module 22, and passes through an ocular 26 to be observed by a user. A laser beam B is emitted by the laser diode 52, is reflected by a reflecting mirror 60 to enter the prism module 22, passes through a pentagon prism 222, is reflected by a quadrangle prism 224 (Pechan prism) to leave the prism module 22, and is projected to an object (not shown) through an objective module 24. The object reflects the laser beam B to generate a laser beam C. The laser beam C enters a prism module 12 through an objective module 14 of the left optical system 10, is reflected by a quadrangle prism 124, passes through a pentagon prism 122, is reflected by a reflecting mirror 62, and is received by a laser receiver 54. Visible light beams A, A′ respectively pass through the objective modules 14, 24 and Schhmidt-Pechan prisms of the prism modules 12, 22 to form an erect image, and the erect image can be observed through an ocular 16 and the ocular 26. The visible light beams A, A′ received by the binocular are utilized to form an erect image of the object for an observation by the user, and the laser beam B emitted by the binocular is utilized to measure the distance from the binocular to the object.
In the structure described above, the laser diode 52 is arranged to be disposed near the ocular 26 so as to avoid the organic light-emitting diode (OLED) 63. However, the arrangement of the laser diode 52 is disadvantageous to the appearance design of the ocular 26.
FIG. 2 depicts the internal structure of another prior binocular capable of measuring distance, wherein the laser diode 52 and a laser receiver 54 are respectively disposed near objective modules 50, 50′. Because a transmissive-type organic light-emitting diode (OLED) has not been available and a general organic light-emitting diode (OLED) does not meet the requirements, a transmissive liquid crystal display (LCD) is used to be disposed on the light path.